Air conditioning system



1966 w. HOCHSTRASSER AIR CONDITIONING SYSTEM Filed July 11, 1963 5 Sheets-Sheet 1 4 l AP=/3 ,2 Fig.2 v

Names Hochinnssea INVENTOR X i g 1966 w. HOCHSTRASSER 3,283,808

AIR CONDITIONING SYSTEM Filed July 11, 1963 5 SheetsSheet 2 INVENTOR BY His/W Nov. 8, 1966 w. HOCHSTRASSER 3,283,808 AIR CONDITIONING SYSTEM Filed July 11, 1963 3 Sheets-Sheet 5 Fig.6

Fig.7

59 60 I 70 58 f 2 Q66 57 55 ;1 l g /fl77 g ---e- Herman H odutnnssts INVENTOR United States Patent Ofllice 3,283,808 Patented Nov. 8, 1966 8 Claims. in. ins-22 The present invention relates to an improved air conditioning system or apparatus of the type provided with a plurality of spatially separated air conditioning units, the respective heat exchangers of which are arranged in a closed circuit with at least one central station heat exchanger through the agency of a conduit network or system for conveying a working medium, such as a heat carrier medium or fluid or a cooling medium with the aforesaid heat exchanger of each conditioning unit being connected in parallel to one another. It is to be distinctly understood that the air conditioning apparatus of the present invention can be effectively employed for heating or cooling any of the enclosures or areas to be conditioned, as the situation may require, and thus, the term air conditioning as employed herein is to be understood in its broader sense as just explained.

Air conditioning systems have become known to the art of the type in which-for modulation of the pressure differences appearing during operation of the installation between the inlet of the throttle valve connected in front of the heat exchanger of each air conditioning unit and the outlet of the corresponding heat exchanger, which pressure diiierences with changes of the throughflow quantity or flow rate due to displacement of the throttling valve are subjected to a variable influence-there is provided a so-called reverse return flow also designated as a Tichelmann-circuit. In addition to such, and for the purpose of preventing a pronounced increase of the pressure differences during throughflow of partial or component quantities through the individual air conditioning units arranged at the outlet of the heat exchanger at the central station, there is employed a throttle valve, for example after the central heat exchanger, which regulates the pressure difference to a constant pressure over a representative measuring section, for example at one of the air conditioning units. In this manner, the pressure difference across all other units is also maintained approximately constant, particularly by careful construction of the cross-sections of the flow conduits. It has been noted, however, that with the larger air conditioning installations embodying a plurality of individual air con ditioning units and by virtue of the practically doublelaying or guiding of the return flow conduit and the required increased dimensioning of the conduits, there results a considerable increase in costs.

Thus, it is a primary object of the present invention to provide an improved air conditioning apparatus by means of which such a double running and overdimensioning of the return flow conduit can be prevented, and nonetheless the pressure difierence between the inlets of the respective throttle valves and the outlets of the associated air conditioning units can be maintained constant and uniform with respect to one another.

A further important object of the present invention is to provide an improved air conditioning system for reliably furnishing heating and cooling of the enclosures or areas served thereby, allowing for generally cheaper installation of the system.

Still another object of the invention is to provide an improved air conditioning system which assures positive and adequate heating or cooling at all times of the areas or enclosures served thereby, employing a conduit network and system which is relatively simple and economical to install.

The air conditioning apparatus of the present invention generally comprises at least one central heat exchanger, an infeed conduit system and a return flow conduit system for the working fluid medium. as well as a number of heat exchangers of the spatially separated room air conditioning units, each arranged in a parallel connection between the infeed and return flow conduits, as well as throttle members arranged in front of these unit heat exchangers. The invention apparatus: further comprises a pump in the infeed or return flow conduits for the circulation of the working medium under pressure, and is particularly manifested by the features that each parallel connection is provided with a pressure regulator, the measurement section or unit of which, on the one hand, is operatively connected with the inlet of the associated throttle member and, on the other hand, with the outlet of the associated air conditioning unit, in order to maintain the pressure drop through such throttle member and the associated air conditioning unit constant, independent of adjustment of the throttlemember and the operating conditions of the system.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawings:

FIGURE 1 schematically illustrates a two-pipe duct or conduit system of an air conditioning apparatus of the present invention;

FIGURE 2 is a vertical cross-sectional view taken through a pressure differential regulator adapted to be employed in the apparatus of FIGURE 1;

FIGURE 3 schematically illustrates a further embodiment of a two-pipe duct or conduit system of an air conditioning apparatus of the invention;

FIGURE 4 is a vertical, cross-sectional view taken through a pressure differential regulator adapted to be employed in the system of FIGURE 3;

FIGURE 5 schematically illustrates a three-pipe" conduit system of an air conditioning apparatus of the present invention;

FIGURE 6 schematically illustrates a further embodiment of a three-pipe conduit system; and

FIGURE 7 is a cross-sectional view of a regulating gate or slide for the conduit system depicted in FIGURE 6 and as adapted for use in the system of FIGURE 5.

Referring now to the drawings, wherein like reference numerals generally denote similar elements, in FIGURE 1 there is depicted a conduit network with reference numeral 1 designating for instance a hot water inteed conduit or duct system connected to a central station heat exchanger 2, for example in the form of a boiler. The heat exchanger 2 is supplied by a suitable circulating pump 3 arranged for instance in the return flow conduit or duct 4 in front of the aforesaid heat exchanger 2. Between the infeed conduit system 1 and the return flow conduit system 4 there extend a plurality of parallel conduits or duct connections 5, each of which having associated therewith a room air conditioning unit including a heat exchanger, as generally designated by numeral 6. Upstream with respect to each air conditioning unit 6 and in each parallel connection 5 there is arranged a throttle valve 7 permitting throttling of the quantity of water or working medium flowing through the corresponding air conditioning unit 6. The adjustment of the individual throttle valve 7 can thus be controlled manually or through the agency of a room thermostat, as is well known to the art.

During circulation of the water which is heated in the heat exchanger 2 the pressure in the infeed conduit system 1 decreases with increased distance from the circulating pump 3. Likewise, the pressure still appearing in the return form flow conduit 4 also decreases in the direction towards the aforesaid circulating pump. As a result, varying pressure differences appear between the connections to the different parallel conduits at the infeed conduit system 11 and the return flow conduit system 4, whereby the pressure diiference between the infeed and return flow system 1, 4 is the largest in the region of the circulating pump 3 and smallest atthe furthest spac ing from said pump. Such pressure differences will additionally increase if only reduced quantities are permitted to flow through the individual air cOnditiOning units 6, corresponding to a throttling by means of the associated throttle valve 7, since in this instance the pressure loss from the heat exchanger 2, infeed conduit 1 and return flow conduit 4 in consequence of the reduced quantity becomes smaller, whereas the pressure of the circulating pump 3 under these circumstances generally increases slightly.

In order to achieve that the pressure diiference between the inlet to the respective throttle valve 7 and the outlet from the associated air conditioning unit 6 in all parallel connections 5 remains the same independent of the distance from the pump 3 and independent of the throughflow quantity of water, a pressure regulator 8 is arranged in each parallel duct or connection 5, which in the illustrated embodiment is shown to be connected in front of its associated throttle valve 7. Advantageously, the measuring unit or sect-ion of each such pressure regulator 8 is subjected, on the one side, to the pressure of the water at the inlet of the corresponding parallel connection 5 and, on the other side, is subjected to the pressure appearing at the outlet of the corresponding air conditioning unit 6. A control line or conduit 9 is provided at each parallel connection 5, as shown, which connects the outlet of the associated air conditioning unit 6 wit-h the measuring section of the corresponding pressure regulator 8, in order to transmit the pressure appearing at the outlet of the aforesaid air conditioning unit to the measuring section of the aforesaid corresponding pressure regulator. The pressure difference between the inlet of each throttle valve 7 and the outlet of the corresponding air conditioning unit 6 can be maintained constant by means of the associated pressure regulator 8 controlled in dependence of such pressure dilference.

In FIGURE 2 there is illustrated a vertical, crosssectional view of a valve mechanism suitable as a pressure regulator 8 in any of the parallel conduits 5 of the air conditioning system shown in FIGURE 1. Reference numeral 11 generally designates a housing which is closed at its upper end by means of a cover member 12. At the lower end of this housing 11 there is connected a housing portion 13. A diaphragm or membrane 14 is fixedly clamped between the housing 11 and the housing portion 13 and forms part of the measuring section or unit of the pressure regulator 8. An inlet connecting piece or nipple 15 opens into the housing 11, as shown, and forms a valve seat at its inner bent or flexed end 16. A valve disk 17, preferably formed of an elastic material, cooperates with this valve seat 16, said valve disk being connected to a bracket or valve rod 18.

The valve rod 18 which grips about or encircles the inlet connecting piece end 16 is riveted to a spring plate 19 bearing against the undersurface of the diaphragm 14. The spring plate 19 is guided by means of its shaft or pin member 20 in the bore of an adjustment sleeve 21, said adjustment sleeve being threadably connected with an internally threaded projection piece or neck 22 of the housing portion 13. The bore of the projection piece 22 is closed to the outside by means of a screw cap 23. The adjustment sleeve 21 carries an abutment or support surface 24 for a pressure spring 25 acting against the spring plate 19 and having the tendency to displace such spring plate 19 upwardly, to thereby raise the valve disk 17 from the valve seat 16 through the agency of the valve rod 18.

In the housing portion 13, the inner compartment of which is separated via the diaphragm 14- from the inner compartment of the housing 11, there opens the bore of a connecting piece or nipple 26 serving as the connection to the associated control line or conduit 9. On the other hand, whereas the inlet connecting piece 15 is connected to the infeed side of the parallel connection 5, the inner compartment of the housing 11 is connected via a discharge connecting piece or nipple 27 with the inlet of the throttle valve 7.

During operation of the installation the pressure prevailing in the inner compartment of the housing 11 works against one face of the diaphragm 14 and, on the other hand, the pressure prevailing in the outlet of the air conditioning unit 6 is transmitted through the associated control line 9 to the inner compartment of the housing portion 13, with this last-mentioned pressure working against that prevailing in the housing 11. The pressure appearing in the housing 11 also works against the force of the spring 25, such spring force being settable or changeable by displacing the adjustment sleeve 21. Both of the pressures operating against the underface of the diaphragm 14 are maintained in equilibrium with the pressure working against the upperface of such diaphragm in that, with an increase of the pressure in the inner compartment of the housing 11 the diaphragm 14 is pressed downwardly and thereby the valve disk or plate 17 is moved towards the valve seat 16 via the valve rod 18, such that the throughflow is throttled and the pressure in the inner compartment of the housing 11 again falls or drops.

If the flow resistance changes due to displacement of the throttle valve 7 in the sense of an increase of the fluid quantity flowing through the associated air conditioning unit 6, then the pressure difference across the throttle valve 7 and such air conditioning unit 6 becomes smaller, resulting in a decrease of the pressure difference acting against the diaphragm 14 of the associated pressure regulator 8. Consequently, the valve disk 17 is displaced via the valve rod 18 away from the valve seat 16 until the pressure difference at both sides of the diaphragm 14, which corresponds to the pressure drop through the throttle valve 7 and the air conditioning unit 6, is again returned to the value governed by the spring 25. Due to maintaining constant the pressure difference the regulation of the throughflow quantity through the associated throttle valve 7 becomes more exact. Likewise, a modulation of the pressure drop in the system during installation of the air conditioning apparatus is practically no longer necessary.

In the embodiment illustrated and described with re.- spect to FIGURES 1 and 2 each of the pressure regulators 8 is arranged at the inlet to the associated throttle valve 7 and the respective control lines or conduits 9 are connected with the outlet of the corresponding air conditioning unit 6. Instead of such an arrangement, pressure regulators could also be arranged at the outlet of the associated air conditioning units, whereas the control conduits in such case transmit the pressure appearing at the inlet to the throttle valve, such an arrangement being schematically depicted in FIGURE 3.

In FIGURE 3 the elements similar to those previously described with reference to the embodiment of FIGURES 1 and 2 have here again been designated by the same reference numerals. Since in the embodiment of FIGURE 3, the pressure regulators 8 of FIGURES 1 and 2 are not placed at the inlet side of the associated throttle valves 7, but instead, pressure regulators 8' of somewhat different construction are arranged at the outlet side of the associated air conditioning unit 6, each such pressure regulator 8 must work in an opposite direction to the pressure regulator 8 depicted in FIGURE 2. In order to render such possible, the pressure regulators 8 each embody the construction depicted in FIGURE 4.

Directing attention now to this figure, it will be recognized that each such pressure regulator 8' comprises a housing formed of three housing portions 30, 31 and 32. Between the two outermost housing portions and 32 and the central portion 31 there are clamped two membranes or diaphragms 33 and 34, as shown. The diaphragms 33 and 34 divide the inner compartment of the regulator housing into an inlet chamber 35, a return flow chamber 36 and a control chamber 37. The control line or conduit 9 (FIGURE 3) opens into the control chamber 37 via the connecting piece or nipple 38. The return chamber 36 contains an outlet feed pipe or stud 39 operably connected with the return flow conduit 4 as well as an inlet feed pipe or stud 40 which is operatively connected with the associated heat exchanger of each air conditioning unit 6. A channel 41 branching-off from the inlet feed pipe 40 opens into the inlet chamber and permits exposing the diaphragm 34 to the pressure appearing at the outlet or return flow side of the associated air conditioning unit 6. The inlet feed pipe leading into the interior of the return flow chamber 36 is bent at its inner end and forms a valve seat or opening 42 scalable by means of a valve disk 43 acted upon or influenced by the diaphragm 33. The valve disk 43 is held by a sleeve 44 provided with diametrically opposed openings 45, its upper end communicating with a plate member 47. The diaphragm 34 bears at its central region against this plate member 47, said central region being placed under load by a pressure spring 49 via a plate member 48. The upper end of the pressure spring 49 rests against an adjust ment screw 50 threaded into the housing portion 32.

As has already been mentioned, during the operation of the system depicted in FIGURE 3 the diaphragm 33 is subjected to the pressure appearing at the inlet side of the associated throttle valve 7. On the other hand, there works in the opposite direction against the diaphragm 34, in addition to the pressure appearing at the oulet of the associated heat exchanger of the air conditioning unit 6 transmitted via the channel 41, the force of the pressure spring 49 governed by the adjustment screw 50. Thus, there is applied against the sleeve member 44 two oppositely operating forces which determine the position of the valve disk 43 relative to the valve seat or opening 42. Both of the aforementioned forces maintain an equilibrium condition with a given adjusted reference value determined by the setting of the adjustment screw 50, and thereby permits the outflow of the working medium leaving the heat exchanger of the air conditioning unit 6 via the return flow chamber 36 and the outlet pipe stud 39.

If the pressure difference in the control chamber 37 and the inlet chamber 35 changes, for example in the sense of an increase of such pressure difference, then the diaphragm 33 subjected to the higher pressure moves upwardly and guides the valve disk 43 towards. the valve seat or opening 42. Consequently, the quantity of working medium discharged through the valve opening 42 is throttled, whereby the pressure at the outlet side of the heat exchanger of the associated conditioning unit 6 increases. Conversely, the pressure drop of the working medium decreases during throughflow through the throttle valve 7 and the heat exchanger of the associated air conditioning unit 6. As a result, the pressure difference between the control pressure chamber 37 and the inlet chamber 35 again becomes smaller, resulting in an opening movement of the valve disk 43. Consequently, the equilibrium condition of the opening and closing forces operating in the regulator 8' is again maintained.

It is to be noted that the pressure of the working medium in the return flow chamber 36 does not influence the function of the regulator 8 since both of the diaphragms 33 and 34 are supported on top of one another via the sleeve 44 and the pressure in such chamber is not only smaller than that in the control chamber 37, but

r duits 1 and 1 a respective parallel branch conduit 5' and 5, again the pressure difference across all air conditioning rather, also smaller than the pressure appearing in the inlet chamber 35. The return flow chamber 36, as mentioned, .is continuously operatively coupled with the return flow conduit 4. While for convenience in description the conduit network described with reference to the embodiments of FIGURES 1 to 4 was supplied with hot water, it is to be appreciated that it would also be possible to use the air conditioning units 6 for cooling purposes in which case cold or cooled water or suitable working medium would then be circulated through the system.

As can be seen by inspecting FIGURE 5 the threepipe system exhibits a conduit network comprising two infeed conduits l and 1" as well as the return flow conduit 4, with there being provided from both of the infeed con- 5" for each air conditioning unit 6. A changeover or reversal throttle valve 7 is arranged in front of, that is at the inlet side of each air conditioning unit 6,. both of the inlets of said reversal throttle valve are operatively coupled via a respective pressure regulator 8 with the corresponding parallel branch conduit 5' and 5", respectively. These pressure regulators 8 may advantageously be of the type described and shown with respect to the discussion of FIGURE 2. Both of the infeed conduits 1 and 1" conduct in known manner working medium, such as for instance hot water and cold water, respectively, prepared in the central heat exchangers 2' and 2", respectively. Both of the heat exchangers 2 and 2 are supplied with water from the return flow conduit 4 through the agency of a common feed pump 3. i

In the operation of the system according to FIGURE units 6 and their associated throttle valve 7 is maintained constant, not withstanding the fact that, as the situation might require, not all of such air conditioning units are supplied with the same medium, for example cold water. Such constant and uniform or predetermined pressure drop across all air conditioning units 6 is achieved in that, the outlet of each aforesaid unit 6 is connected through-the associated regulator 8 with both inlets. of the associated reversal throttle valve 7, the latter to be fully described shortly, via a branched control line 9 and, thus, influences or controls both regulators 8. Naturally, however, only that regulator 8 is operative which lies in the branch conduit 5 or 5" opened by the reversal throttle valve 7, that is, the branch conduit 5' or 5" which is then operably coupled for throughflow with the corresponding air conditioning unit 6.

With the reversal throttle valve 7 one is concerned in principle with a three-way valve which, however, is simultaneously in a position to quantitatively control the infeed out of the connecting branch to the associated air conditioning unit 6. A valve of this type is illustrated by way of example in FIGURE 7 wherein, moverover, the therein illustrated construction has still further functions, as will be apparent from the discussion to follow. It is further to be mentioned that actuation of the reversal throttle valve 7 takes place through a servomotor which, for example, is controlled by the room temperature.

The embodiment depicted in FIGURE 6, wherein like reference numerals again denote similar elements, differs from that of FIGURE 5 insofar as a regulator 8' is arranged at the outlet of each air conditioning unit 6 whereby, however, care must be taken that each such regulator 8 is always subjected, via .the control line 9, with that working medium which in this period of time flows through the associated air conditioning unit. For this purpose, the reversal throttle valve 7" shown in section in FIGURE 7 is employed, and which at the same time is also in a position to operatively couple the control line 9 with that branch conduit 1 or 1" which momentarily is coupled with the air conditioning unit 6. 'In this instance, each regulator 8' may advantageously possess the construction depicted and described with reference to FIGURE 4.

Directing attention now to FIGURE 7, the throttle valve 7" comprises a housing 52 provided with inlet connections or studs 53 and 54 as well as an outlet connection or stud 55. In the housing 52 there is slidably arranged a valve slide or spool 56 which extends via a actuating rod 57 provided at its upper end piercingly through a guide and packing sleeve 58 threadably received in the housing 52, with the aforesaid actuating rod operatively connected with the servomotor 90. The valve slide 56 extends through two sealing lip rings 59 and 60 advantageously arranged above and beneath the outlet stud or connection 55, as shown, to divide the interior of the housing 52 into three chambers or compartments 61, 62 and 63. The valve slide 56 carries at. its central region four, lengthwise extending V-shaped slots or grooves 64 which, depending upon the position of the valve slide 56 relative to the sealing rings 59 and 60, operatively couple with a predetermined throughfiow cross-section the one or the other of the inlet chambers 61 or 63 with the outlet chamber 62. The construction of the valve 7" described up to the present is sufiicient to achieve a switching and throttling of the working medium supplied to the corresponding air conditioning unit 6, and therefore fulfills the requirements of the throttle valve 7 of FIGURE 5.

As can further be seen from FIGURE 7, an extension cap 65 is threadably connected to the lower end of the housing 52 containing two further sealing lip rings 66 and 67. Intermediate the two sealing rings 66 and 67 there opens a connecting channel or bore 68 which serves to communicate the control line 9 with an outlet pipe or stud 69. An auxiliary slide 70 is provided at the lower end of the valve slide 56 which, in the illustrated upper terminal position of the valve slide 56, extends into the sealing ring 66 and thereby closes the chamber 63 with respect to the inner compartment 71 of the extension cap 65. The auxiliary slide 70 is provided with a notch 72 at the portion of such slide 70 which connects to the valve slide 56, this notch 72 in its lower terminal position arriving in the zone of the sealing ring 66. The auxiliary slide 70 is further provided with a longitudinal bore 73 which extends through a portion of the valve slide 56 and in the upper terminal position of the latter opens into the compartment or chamber 61.

If it is assumed that the connecting stud or piece 53 is connected with the warm water infeed and the connecting stud 54 with the cold water infeed, then the corresponding air conditioning unit 6 connected via the outlet connection 55 will be supplied with warm water, in the illusstrated position of the valve slide 56 shown in FIGURE 7. At the same time the pressure in the chamber 61 is operative via the longitudinal bore 73, the chamber 71, the bore 69 and the conduit 9 at the regulator 8' positioned as shown in FIGURE 6. Now, if the valve slide 56 is downwardly displaced then the throughfiow passage from the hot water inlet 53 to the outlet 55 is gradually closed at the sealing ring 59. If the valve slide 56 moves further downwards then, first of all, the throughpassage between the hot water inlet 53 and outlet 55 is completely closed by the sealing ring 59. A short time later the end of the slide member 70 enters the sealing ring 67, whereby also the connection between the hot water inlet 53 and the bore 69 is interrupted. With further axial movement the connection between the cold water inlet 54 and the channel or bore 68 through the sealing ring 66 is freed via .the notch 72 and, if the valve slide moves further, the sealing ring 60 via the notches 64 gradually frees the path from the chamber 63 to the chamber 62 and then to outlet 55.

As a result, there takes place a forced accommodation of the control pressure influencing the regulator 8' to the working medium flowing through the associated air conditioning unit 6.

While there is shown and described present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.

Having thus described the present invention, what is desired to be secured by United States Letters Patent is:

1. Air conditioning system comprising at least one central heat exchanger, a conduit network including infeed and return feed conduit means and parallel branch connections therebetween for a fluid working medium, a plurality of spatially separated air conditioning units each operatively connected with one of said parallel branch connections between said infeed and return feed conduit means, throttle means communicating with each of said air conditioning units, a pump provided in said conduit network for circulating said working medium under pressure, a pressure regulator provided for each parallel branch connection, each pressure regulator including a measuring unit connected at one side with the inlet of the associated throttle means and at the other side with the outlet of the associated air conditioning unit for maintaining the pressure drop through such throttle means and its associated air conditioning unit constant independent of the setting of such throttle means and the operating conditions of the system.

2. Air conditioning system comprising at least one central heat exchanger, a conduit network including infeed and return feed conduit means and parallel branch con nections therebetween for a fluid working medium, a plurality of heat exchangers of spatially separated room air conditioning units each arranged in one of said parallel branch connections between said infeed and return feed conduits means, throttle means arranged in front of each of said heat exchangers of said room air conditioning units, a pump provided in said conduit network for circulating said working medium under pressure, a pressure regulator provided for each parallel branch connection, each pressure regulator including a measuring unit connected with the inlet side of the associated throttle means and with the outlet side of the associated room air conditioning unit for maintaining the pressure drop through such throttle means and its associated air conditioning unit constant independent of the setting of such throttle means and the operating conditions of the system.

3. Air conditioning system according to claim 2 wherein each pressure regulator is arranged at said outlet side of its associated room air conditioning unit, control line means for connecting said pressure regulator to said inlet side of its associated throttle means.

4. Air conditioning system according to claim 2 wherein each pressure regulator is arranged at said inlet side of its associated throttle means, control line means for connecting said outlet side of the associated room air conditioning unit of each parallel branch connection to its associated pressure regulator.

5. Air conditioning system according to claim 2 wherein there is provided a separate central heat exchanger for a heating working medium and for a cooling working medium, said conduit network including separate infeed conduit means for each heating and cooling working me dium and common return feed conduit means for both aforesaid working mediums, each of said throttle means including two inlets and being constructed to operate as a reversing mechanism, one said pressure regulator arranged at each of said inlets of said throttle means common control line means operatively connecting said measuring units of both pressure regulators to the outlet side of the associated air conditioning unit.

6. Air conditioning system according to claim 2 whereine there is provided a separate heat exchanger for a heating working medium and for a cooling working medium, said conduit network including separate infeed conduit means for each heating and cooling working medium and common return feed conduit means for both aforesaid working mediums, each of said throttle means being provided with two inlets and being constructed to operate as a reversing mechanism, each said pressure regulator being arranged at said outlet side of its associated conditioning unit, control line means for operably connecting each said pressure regulator with a reversal valve operably coupled with the associated reversing throttle means.

7. Air conditioning system according to claim 6 wherein each reversal valve forms a part of its associated reversing throttle means, each reversing throttle means including a reversal slide member, each reversal valve including an auxiliary slide operably coupled with said reversal slide member, said auxiliary slide having an outlet which depending upon the position of said reversal slide member operably communicates with one of said two inlets of said reversing throttle means.

8. Air conditioning system comprising at least one central heat exchanger, a conduit network including infeed and return feed conduit means and parallel branch connections therebetween for a fluid working medium, said infeed and return feed conduit means having an inlet side and an outlet side respectively, located at the same end of said conduit network, a plurality of spatially separated air conditioning units each operatively connected with one of said parallel branch connections between said infeed and return feed conduits means, throttle means communicating with each of said air conditioning units, a pump provided in said conduit network for circulating said working medium under pressure, a pressure regulator provided for each parallel branch connection, cache References Cited by the Examiner UNITED STATES PATENTS 4/1965 Windham 165-22 ROBERT A. OLEARY, Primary Examiner. CHARLES SUKALO, Examiner. 

1. AIR CONDITIONING SYSTEM COMPRISING AT LEAST ONE CENTRAL HEAT EXCHANGER, A CONDUIT NETWORK INCLUDING INFEED AND RETURN FEED CONDUIT MEANS AND PARALLEL BRANCH CONNECTIONS THEREBETWEEN FOR A FLUID WORKING MEDIUM, A PLURALITY OF SPATIALLY SEPARATED AIR CONDITIONING UNITS EACH OPERATIVELY CONNECTED WITH ONE OF SAID PARALLEL BRANCH CONNECTIONS BETWEEN SAID INFEED AND RETURN FEED CONDUIT MEANS, THROTTLE MEANS COMMUNICATING WITH EACH OF SAID AIR CONDITIONING UNITS, A PUMP PROVIDED IN SAID CONDUIT NETWORK FOR CIRCULATING SAID WORKING MEDIUM UNDER PRESSURE, A PRESSURE REGULATOR PROVIDED FOR EACH PARALLEL BRANCH CONNECTION, EACH PRESSURE REGULATOR INCLUDING A MEASURING UNIT CONNECTED AT ONE SIDE WITH THE INLET OF THE ASSOCIATED THROTTLE MEANS AND AT THE OTHER SIDE WITH THE OUTLET OF THE ASSOCIATED AIR CONDITIONING UNIT FOR MAINTAINING THE PRESSURE DROP THROUGH SUCH THROTTLE MEANS AND ITS ASSOCIATED AIR CONDITIONING UNIT CONSTANT INDEPENDENT OF THE SETTING OF SUCH THROTTLE MEANS AND THE OPERATING CONDITIONS OF THE SYSTEM. 